1. Field of the Invention
The present invention relates to a piezoelectric film type actuator used for a liquid discharge head, a sound generating device, such as a microphone, a speaker, various kinds of vibrators or oscillators, as well as a sensor or the like, and also, relates to the method of manufacturing the same. Further, the invention relates to a liquid discharge head that uses the piezoelectric film type actuator, and the method of manufacture therefor. In this respect, the piezoelectric film type actuator referred to in the subject specification is a member that converts electric energy to mechanical energy such as to effectuate mechanical displacements, vibrations, or stresses. Also, it is a member that reverses such a conversion.
2. Related Background Art
In recent years, there has been a demand for a displacement element for adjusting the length and the position of optical path on a sub-micron order or a sensing element for detecting micro displacements as electrical changes in the fields of optics and precision processing. To meet this demand, there has been in progress a development of a piezoelectric film type actuator, which is a member that utilizes the displacement or the inverse phenomenon thereof based on the reverse piezoelectric effect or electric distortion when an electric field is applied to the piezoelectric or electrically distortional material of a ferroelectric element.
Also, conventionally, it has been preferred to adopt the unimorph type or the bimorph type for the formation of a piezoelectric film type actuator used for the liquid discharge recording head or the like. In this respect, for the liquid discharge recording apparatus that uses a piezoelectric film type actuator of the kind for the enhancement of the printing quality and the printing speed, among some others, in order to meet such demand, the development has been in progress for the implementation to make the piezoelectric film type actuator smaller at a higher density, which can be driven at a lower voltage, but with a higher response performance, as well as for the provision of an elongated multiple nozzle.
Now, in order to obtain a large flexure displacement, a generating power, or a generation potential with the aforesaid unimorph- or bimorph-piezoelectric film type actuator, it is important to make the base plate that becomes the oscillating plate thinner. Here, however, the thickness of such a base plate is decreased and the strength thereof is reduced, leading to the problem that the smoothness is eventually reduced. Further, there is a problem for the conventional unimorph- or bimorph-piezoelectric film type actuator that the reliability thereof is marred due to the use of a bonding agent.
To overcome these problems, it is disclosed in the specification of Japanese Patent Application Laid-Open No. 62-213399 an increased bonding strength is provided by sintering piezoelectric ceramics and ceramics oscillating plate at a time without using any bonding agent.
However, in this method, different materials are sintered at high temperature. As a result, the oscillating plate and the piezoelectric ceramics are shrunk themselves, making it difficult to adjust the dimensional precision in the order of a micron on a large area. For that matter, the highly reliable piezoelectric film type actuator having a large area, or the liquid discharge head, can hardly be obtained.